Henrardia, a new genus of the Gramineae

Most classifications of the genera of the Gramineae have been on the structure and arrangement of their spikelets, for these organs provide a far greater variety of readily distinguishing characters than do other parts of the grass plant. Nevertheless it has not always been possible to decide from morphological studies alone whether marked similarities in structure point to a close affinity or are merely examples of parallel development. The modern taxonomist, endeavouring to arrange the grass genera in as natural a sequence as possible in order to emphasise relationships and evolutionary trends, sooner or later meets with difficulties in this respect, for examples of parallelism are of common occurrence in this family. He is more fortunate, however, than his predecessors, in that his own intensive morphological studies, based on a wider range of specimens, may be supplemented by additional data gleaned from the ecological, anatomical and cytological researches of contemporary workers. Thus aided by the more complete information at his disposal, it has been possible for him to rearrange certain groups, particularly the Festuceae and Hordeeae, in which parallel development has occasionally led to unrelated genera such as Lolium, Agropyron and Nardus, being too closely associated. In the following account an attempt has been made to provide a more natural classification for about eighteen species frequently referred to the genus Lepturus R. Br. by reason of their similar spicate inflorescences.